Electronic structure, magnetic and optic properties of spinel compound NiFe 2 O 4

Abstract We report ab initio investigation of structural, electronic, magnetic and optical properties of the NiFe 2 O 4 compound. Hubbard parameters are computed for both Ni and Fe atoms. Employing generalized gradient approximation (GGA) and GGA + U approximations and taking into consideration four possible types of atomic arrangements, we identify the most stable structural–magnetic configuration of the system. Interestingly, the inverse spinel NiFe 2 O 4 compound is found to exhibit a ferrimagnetic structure. The ground state structural lattice parameters and the interatomic distances of spinel NiFe 2 O 4 compound are computed. Furthermore, band structure calculations demonstrate that NiFe 2 O 4 compound exhibits large band gaps in both spin configurations with a large magnetic moment. Energetically, ferrite nickel favors the inverse spinel phase in which Fe and Ni cations in either octahedral or tetrahedral sites adopt the high-spin configuration. We found that the energy of the normal spinel is higher than that of the inverse spinel, confirming that inverse spinel is the most stable structure of the NiFe 2 O 4 compound. The optical behavior of the NiFe 2 O 4 compound is characterized by calculating the real and imaginary part of the dielectric function, the absorption coefficients, the refractive index, the optical conductivity and the energy loss. Optimizing structural, electronic, magnetic and optical properties of this novel compound is crucial for exploring and utilizing it for modern device applications.